Asymmetric Induction on Copper(I) Chloride catalyzed 1,4-addition of alkylmagnesium chlorides to ?, ?-disubstituted (E)-enoylsultams and subsequent protonation
作者:Wolfgang Oppolzer、Arend J. Kingma
DOI:10.1002/hlca.19890720622
日期:1989.9.20
Successive treatment of conjugated N-enoylsultams 2 with alkyl Grignard reagents/CuCl and aq. NH4Cl solution generated selectively two stereogenic centers at C(α) and C(β) providing, after flash chromatography and crystallization, acylsultams 5 in high purity. Mild cleavage afforded the recovered sultam auxiliary 1 and enantiomerically pure carboxylic acids 7.
作者:Stephen G. Davies、Isabelle M. Dordor-Hedgecock、Kevin H. Sutton、Jonathan C. Walker、Richard H. Jones、Keith Prout
DOI:10.1016/s0040-4020(01)88065-0
日期:1986.1
to the E-crotonyl complex (RS)-[η5-C5H5)Fe(CO)-(PPh3)COCHCHMe] followed by trapping of the resultant enolate with methyl iodide gives (RS)-[(η5-C5H5)Fe(CO)(PPh3)COCH(Me)CHMe2] (d.e. > 100:1), also generated by treatment of (RS)-[(η5-C5H5)Fe(CO)(PPh3)COCH2CH(OMe)2] with three equivalents of methyllithium and methyl iodide. Addition of -butyllithium to the (RS)-E-crotonyl complex followed by protonation
迈克尔加成甲基锂到E-巴豆络合物(RS) - [η 5 -C 5 H ^ 5)的Fe(CO) - (PPH 3)COCHCHMe],随后用甲基碘将所得烯醇化物的捕集,得到(RS) - [(η 5 -C 5 H ^ 5)的Fe(CO)(PPH 3)COCH(Me)中CHME 2 ]的(de> 100:1),也通过处理(RS)的生成- [(η 5 -C 5 H 5)Fe(CO)(PPh 3)COCH 2 CH(OMe)2 ]与三当量的甲基锂和甲基碘。除此之外-丁基锂生成(RS)-E-巴豆酰基络合物,然后用甲醇质子化,具有非对映选择性高。用甲基碘淬火得到(RS) - [(η 5 -C 5 H ^ 5)的Fe(CO)(PPH 3)COCH(Me)的CH(Me)中-Bu],也通过处理任一对映异构体的[(η产生5 C 5 H 5)Fe(CO)(PPh 3)COCH 2 CH(Me)OMe]与两个当量
The opposite diastereoselectivity in the alkylation and protonation of enolates
作者:Yoshinori Yamamoto、Kazuhiro Maruyama
DOI:10.1039/c39840000904
日期:——
enoate (5) produces predominantly the syn-isomer (7) having the butyl and methyl groups syn on the carbon chain, while the methylation of the enolate derived from the ester (8) gives preferentially the other diastereoisomer, anti-(6); the diastereoselectivity can be explained by an eclipsed model.
Optically active compound, antiferroelectric liquid crystal composition containing the same, process for producing the same and process for producing optically active carboxylic acid
申请人:Takasago International Corporation
公开号:EP0884309A1
公开(公告)日:1998-12-16
Disclosed is a novel optically active compound which exhibits no antiferroelectric liquid crystal phase but can be incorporated in an antiferroelectric liquid crystal having a high threshold voltage to reduce the threshold voltage thereof, an antiferroelectric liquid crystal composition containing the compound, a process for the reduction of the threshold voltage of an antiferroelectric liquid crystal composition, a process for producing the compound and a process for producing an optically active carboxylic acid as an intermediate.